His sister had vowed to walk barefoot and unveiled. He mentioned this to the Messenger of Allah ﷺ, who said, "Tell her to ride, to cover her head, and to fast for three days."
حدثنا علي بن محمد حدثنا عبد الله بن نمير عن يحيى بن سعيد عن عبيد الله بن زحر عن أبي سعيد الرعيني أن عبد الله بن مالك أخبره أن
أن أخته نذرت أن تمشي حافية غير مختمرة وأنه ذكر ذلك لرسول الله ﷺ فقال مرها فلتركب ولتختمر ولتصم ثلاثة أيام
Its chain of transmission is daif. Abu Dawud narrated it in the Book of Oaths and Vows, chapter "Whoever sees an atonement upon himself when it involves sin," hadith no. 3293, from the hadith of Yahya, through Ubaydullah bin Zahr, whom the majority of scholars have declared daif. Ibn Main said, "In my view, all his hadiths are daif." It has a daif corroborating narration in Ahmad, 4/147, due to Ibn Lahia, mentioned previously, hadith no. 3293.